Please do not reproduce a similar answer, but explain it. Why does the isocost line drawn like this? why does the isoquant drawn like this? step by step explanations please!

K Q1 Q2 Q L]ustin owns a lot of small urban parking lots and has a choice of either hiring an attendant or buying a parking machine for each lot. He finds that no matter how many cars use his parking lots or how the prices of machines or wages of attendants vary, he always minimizes his costs by buying only one or the other of the two. Draw Justin's isoquant map. ANSEEER: if K (parking machines) and L (attendants) are perfect substitutes, only one of the inputs will be used for any given isocost line. No matter what the isocost line 's slope, we will alwaysget a corner solution ( except where the slope is exactly the same as the slope of the isoquant). in the graph below solid lines are isoquants and the dashed line is an isocost